Pavement.



i PAVEMENT.

' (Appximion meauan. 1o, 190m (No Model.)

WITIJEEE E5:

` UNrrsp STAT-ns PATENT Garros.

FREDERICK J. IVARREN, OE NEWTON, MASSACHUSETTS.

PAVEMENT.

SPECIFICATION forming part of Letters Patent No. 695,421, dated March 11, 1902. v

Application iled January l0, 1902. Serial No. 89,162. (No specimens.)

' ofv Newton, in the `county of Middlesex and State of Massachusetts, have invented a new and useful Improvement in Street Pavements or Roadways, of Whichthe followingis a full, 'clcar, and exact description, reference being had to the accompanying drawings, forming. a part of this specification, in explaining its;

nature.

'Ihe invention is an improvement upon that described in my Letters Patent of the United States No. 675,430, dated June 4, 1901, for an -improvement in pavements or roadways. In; said patent I have described as my invention;

nous cement which can be used in coating the mineral, filling the voidsof the structure, and staying and uniting its elements. I have also' indicated in said patent the sizes of the mineral (stony) pieces which I preferred to use and the proportions which the various sizes should bear tocach other to secure the solidity of base desired Within the limits of the course and have stated that such van association of mineral pieces largely eliminated voids Y between them and decreased the aggregate area of surface to be coated, and thus required the use of substantially the smallest practicable quantity of bituminous Ycement for coating the surface and filling such voids as remained. minous cement thus confined in the voids of such a body of mineral so much larger in volume than it has its flexibility and life preserved to a remarkable degree and so that the strength of its union With the pieces of mineral :increases With the age and use of the pave ment, and an elasticity of the section to traffic and Wear lis obtained which not only does not injure the structure, but, on the contrary, seems to strengthen it y and endow it with greater vitality and conformability to the conditions of Wear. Not only this, but the area I have since ascertained that bituv of bituminous surface exposed to the action of the weather is so decreased by the fact that se large a part of the surface is stony that the disintegratingeflect of atmospheric -iniiuences upon the entire body of cement is very remarkably decre ased. I have new discovered thatfor some uses aditferent grading of the mineral may be had and yet a desirable resultsecured, and while I believe ihatthis and all g'rad'ings which will produce the effect described arecovered by the terms of my said patent itis not specifically statedV and claimed therein. In the-said patent I have indicated that to secure stability in the metal elements of the course combined with of the intermediate sizeand that a very de-` sirable result. can be obtained by the useof the larger elements combined with the smaller elements, as though practically two of the` three gradesmentioned in said patent were used. Inupracticingmy invention I take metal elements from about a half-inch in diameter to about three inches in diameter and com? bine with them metal elementslwhich are about one-tenth of aninch in diameter or less and intimately associate them together uni-y formly and in prearranged proportions in order that the iine elements may have a definite relationto the coarse and so that they may fill theinterstices in and about the coarse elements uniformly from element to elementand' curb to curb. or edge to edge, and so that the metal course shall comprise the4 relatively large elements supported, combined, andasuthe elimination of voids it is desirable thatv sociated with the relatively small elements in a ii`rm,compact, stable,continuous body or layer of practically uniform thickness throughout the course.

thus proportioned is then intimately mingled and combined with a uniting and combining 'weatherproof vehicle or medium, like asphalt or any of its products or coal-tar or any of its f products or a mixture, and so that all the ele- The metal section ofthe course .IOO

ments of the metal course shall be bound together, the interstices remaining filled by it and the whole convertedinto a solid,coherent, continuous body or section of the pavement, in which the mineral elements form by far the largest part of the course, the intention being that the Wear shall be received by the mineral elements and that the uniting vehicle shall act more in the capacity of combining, holding, and weatherproofing rather than as a means for receiving the principal wear, and in this regard ,my present improvement follows the invention of my said patent.

I would here say that one of the great causes of the failure of bituminous pavements is the use of mineral mixtures of so fine a grade and so frictionless a character that separate stability of the mineral itself is not secured and the voids not suliiciently reduced to permit of the best use and protection ot' the bituminous cement. Moreover, such fine mineral mixtures are not calculated to relieve the bituminous cement ot` Wear, the cement forming a large part of the actual wearing-body of the pavement and being thereby subjected tothe disintegrating action of the atmosphere which my invention largely avoids.

I will now describe the invention in connection with the drawings, where- Figure I is a View in cross vertical section of a street-pavement having the features ot' my invention. A conventional foundation only is shown. Fig. 2 is a View in Vertical section, enlarged.

In the drawings the figures represent a vertical section of a pavement. having the features of my invention.

A indicates the upper or wearing section, and it is composed of the mineral elements described combined with each other to form the solid, stable, mineral base specified and the elements of which are coated and the voids thereof filled by bituminous cement, which unites, stays, holds, and weatherproofs the entire section, the whole producing a bituminous macadam course having a Wearing-sur face in which the stone largely predominatcs and takes the principal Wear.

I would not be understood as limiting the invention to the size of the larger and smaller mineral elements described, as it is obvious that some latitude in this may be permitted and the invention still be practiced.

I claimv A Wearing layer of a street sheet-pavement composed ot' a dense mineral body consisting only of relatively large elements, one-half inch and upward in diameter, and relatively small elements, one-tenth of an inch in diameter and less, having predetermined proportions and intimately and uniformly associated throughout the body to eliminate voids, provide stability and a wearing-surface and a uniting weatherproof, bituminous vehicle intimately associated with all the mineral elo` ments serving to combine and unite them, till the voids remaining unfilled and to form with the mineral body a solid, stable, homogeneous, tenacious, elastic, bituminous wearing layer.

FREDERICK J. \VARREN.

W ituesses:

F. F. RAYMOND, 2d, J. M. DoLAN. 

